New JBA Headers On A 2007 Nissan Frontier - More Power And Mileage From New Pipes!

The Install 1. Installing...        read full caption The Install 1. Installing the headers is most difficult on the passenger side of the Frontier, so that's where we'll focus our attention. First things first, the wheel was removed and the truck raised into the air with a hydraulic lift (a jack can also be used).	2. The exhaust system must...        read full caption 2. The exhaust system must first be removed from the catalytic converters by freeing it from the hanger. Once the piping is off the hanger, it can be pushed backward about an inch. Then, the 12mm nuts can be undone and the converters can be pulled from the exhaust manifolds.
3. Here's a look at the cramped...        read full caption 3. Here's a look at the cramped quarters surrounding the factory manifolds. The passenger side is even tighter.	4. In order to remove the...        read full caption 4. In order to remove the passenger-side manifold, we had to pull out the plastic inner fenderwells.	5a. A 12-inch-long extension...        read full caption 5a. A 12-inch-long extension and 18mm socket were used to unbolt the motor mount from the frame.
5b. A jack was used to raise...        read full caption 5b. A jack was used to raise the engine up just high enough to pull out the manifold from the engine bay.	6. If you look closely, you'll...        read full caption 6. If you look closely, you'll spot the blue-colored socket attached to the air ratchet that was used to remove the six nuts holding the manifold to the cylinder head. The nuts are soft and easily rounded off, so a swivel union behind the socket was necessary for removal.	7a. Before the new headers...        read full caption 7a. Before the new headers were installed, the multilayer copper gaskets were smeared with sealant around the exhaust ports to ensure a leak-free fit.
7b. The bolts were tightened...        read full caption 7b. The bolts were tightened in sequence working from the inside of the flange to the outside, which applies equal pressure to the flange for a good seal to the gasket.	(8a & 8b) Once the pipes were...        read full caption (8a & 8b) Once the pipes were in place, the catalytic converters, 02 sensors, and exhaust piping were reinstalled.	8b.
9. Lastly, the motor mount...        read full caption 9. Lastly, the motor mount was lined up and reattached and the wheel put back on the hub. The truck is now ready to run.

The Final Word
The Frontier's 4.0L V-6 is rated at the crankshaft with 261 hp and 285 lb-ft of torque. Our truck put 221 hp and 238 lb-ft of torque to the rear wheels in stock form, as measured by a Dyno Dynamics Dynamometer. That's a 16-percent loss through the drivetrain. Still, our truck routinely averaged between 19 and 21.2 mpg on the highway. The addition of the Cat4ward headers added 9 hp and 6 lb-ft of torque, and we saw a 3-mpg improvement in fuel economy. The horsepower peaked at 5,900 rpm, while the torque fell off at 4,150 rpm.

On the highway, Zippy was still zippy but with a slight growl through the new tubes. The power improvement wasn't noticeable from the seat of our pants, but the increase in fuel economy is substantial.